1/3. Tibial muscular dystrophy with late adult onset in a Spanish family.PURPOSE: We report autosomal dominant distal muscular dystrophy in 5 members of a Spanish family. INTRODUCTION: This unusual muscular disorder has late adult onset and predominantly it affects the anterior compartment of the legs. This myopathy presented clinical and electromyographical characteristics, but unspecific histological findings. Early there have appeared genetical studies, the most frequently used is chromosome linkage, but it is not an absolute criterion for diagnosis, and it is not available in most hospitals. patients DESCRIPTIONS: In our cases walking difficulties appeared between the fourth and fifth decades, characterized by progressive and varied weakness with amyotrophy in the tibial anterior compartment. The electromyography confirmed the presence of a severe non-inflammatory myopathy, chronic and symmetric in the pretibial muscles and of less intensity in the calf muscles. The levels of creatine phosphokinase were normal and muscle biopsy identified a chronic, unspecific lesion with important fibrosis. CONCLUSIONS: The findings, although with some phenotypical differences, were those commonly found in Markesbery-Griggs disease, tibial muscular dystrophy or late onset type 2 distal myopathy. We report a family affected by this muscular disorder, we describe the differential diagnosis and we discuss the review of the available literature.- - - - - - - - - - ranking = 1keywords = muscular dystrophy, dystrophy (Clic here for more details about this article) |
2/3. Early onset distal muscular dystrophy with normal dysferlin expression.A 7-year-old boy, who was noted to be a slow runner at the age of 2 years, had progressive muscle weakness and atrophy, preferentially affecting distal muscles. At 3 years of age, he had scoliosis and difficulty in standing on tip-toe. serum creatine kinase was 1074IU/l. Muscle CT scan showed low-density areas in the lower legs and upper arms, but predominantly in the gastrocnemius and soleus muscles. biopsy of the biceps brachii muscle showed moderate dystrophic changes with normal dysferlin expression on immunohistochemical and western blot analyses. Although muscle involvement mimicked that seen in Miyoshi myopathy (MM), the very early onset of the disease and scoliosis were quite unusual for MM. We, therefore, made the diagnosis of early onset dysferlin-positive distal muscular dystrophy, probably a new type of distal muscular dystrophy.- - - - - - - - - - ranking = 1keywords = muscular dystrophy, dystrophy (Clic here for more details about this article) |
3/3. Different early pathogenesis in myotilinopathy compared to primary desminopathy.Mutations in the human myotilin gene may cause limb-girdle muscular dystrophy 1A and myofibrillar myopathy. Here, we describe a German patient with the clinically distinct disease phenotype of late adult onset distal anterior leg myopathy caused by a heterozygous S55F myotilin mutation. In addition to a thorough morphological and clinical analysis, we performed for the first time a protein chemical analysis and transient transfections. Morphological analysis revealed an inclusion body myopathy with myotilin- and desmin-positive aggregates. The clinical and pathological phenotype considerably overlaps with late onset distal anterior leg myopathy of the Markesbery-Griggs type. Interestingly, all three analyzed myotilin missense mutations (S55F, S60F and S60C) do not lead to gross changes in the total amount of myotilin or to aberrant posttranslational modifications in diseased muscle, as observed in a number of muscular dystrophies. Transiently transfected wild-type and S55F mutant myotilin similarly colocalised with actin-containing stress fibers in BHK-21 cells. Like the wild-type protein, mutated myotilin did not disrupt the endogenous desmin cytoskeleton or lead to pathological protein aggregation in these cells. This lack of an obvious dominant negative effect sharply contrasts to transfections with, for instance, the disease-causing A357P desmin mutant. In conclusion our data indicate that the disorganization of the extrasarcomeric cytoskeleton and the presence of desmin-positive aggregates are in fact late secondary events in the pathogenesis of primary myotilinopathies, rather than directly related. These findings suggest that unrelated molecular pathways may result in seemingly similar disease phenotypes at late disease stages.- - - - - - - - - - ranking = 0.16666666666667keywords = muscular dystrophy, dystrophy (Clic here for more details about this article) |